1. Field of the Invention
The present invention relates to a laminated coil component, a module component that includes a multilayer coil component, and a method of manufacturing a laminated coil component.
2. Description of the Related Art
The electronic component disclosed in Japanese Unexamined Patent Application Publication No. 2013-143471 is known as an example of a conventional laminated coil component. The electronic component disclosed in Japanese Unexamined Patent Application Publication No. 2013-143471 includes a multilayer body, two outer electrodes, and a coil. The multilayer body is formed by laminating a plurality of insulation layers, and contains the coil therewithin. Both ends of the coil are connected to the two outer electrodes respectively by via hole conductors.
Electronic devices are becoming thinner in recent years, and there is demand for lower profiles in laminated coil components. Achieving such lower profiles requires either reducing the number of insulation layers or making the insulation layers thinner. Higher inductance values are also in demand for laminated coil components. Increasing the number of laminated layers, increasing the number of turns in the coil, and so on are useful ways of ensuring a sufficiently high inductance value. It is necessary to make the insulation layers thinner in order to increase the number of insulation layers.
As such, in laminated coil components, there is demand for the insulation layers to be made thinner.
As insulation layers become thinner, the insulation resistance of the insulation layers drops due to small pieces of dust or the like entering when the insulation layers are laminated. This makes it easy for so-called interlayer shorting, where windings of the coil adjacent in the lamination direction short, to occur.
A laminated coil component in which interlayer shorting has occurred is considered defective and must therefore be removed. However, in conventional laminated coil components, interlayer shorting causes a small drop in the inductance value, which makes it difficult to detect that the component is defective even if the inductance value of the coil is measured. There has thus been a problem in that components have been determined to be non-defective despite interlayer shorting occurring therein.
In addition, a laminated coil component is sometimes used as a module such as a DC-DC converter, with an IC or the like mounted on the main surface of the laminated coil component. Here, it is often the case that interlayer shorting is first discovered only after the IC has been mounted. This is because even an extremely small drop in the inductance value has a large effect on the operations of the IC. As such, the laminated coil component alone cannot be removed as defective and is only detected as defective after the entire module, including the IC, has been completed. In principle, an IC that has been mounted once cannot be reused. ICs are expensive products, and more ICs are mounted the larger the module is. Thus, in order to avoid wasting such expensive ICs, it is desirable that defects be detected in a laminated coil component alone before ICs or the like are mounted thereon.